Merge pull request #16 from nickolasteixeira/nick

logic change for permutations - chapter 1

Author: fvntr

Python/chapter01/1.4 - PalinPerm/Nick4.py

@@ -6,7 +6,7 @@
 '''
 
 import unittest
-
+import collections
 
 def palperm(string):
     '''
@@ -15,17 +15,30 @@ def palperm(string):
         string (str): a string to check for all palindrome permutations
     '''
     table = {}
-    count = 0
     for letter in string.lower().replace(" ", ""):
         table[letter] = table.get(letter, 0) + 1
 
+    count = 0
     for key in table:
-        if count > 1:
-            return False
         if table[key] % 2 == 1:
             count += 1
+        if count > 1:
+            return False
     return True
 
+def palperm2(string):
+    letter_frequencies = collections.defaultdict(int)
+    for letter in string.lower().replace(' ', ''):
+        letter_frequencies[letter] += 1
+    
+    odd_frequency_count = 0
+    for frequency in letter_frequencies.values():
+        if frequency % 2 == 0:
+            continue
+        odd_frequency_count += 1
+        if odd_frequency_count > 1:
+            return False
+    return True
 
 class Test(unittest.TestCase):
     def test1(self):
@@ -38,5 +51,15 @@ def test1(self):
         self.assertTrue(palperm(input_string3))
         self.assertTrue(palperm(input_string4))
 
+    def test2(self):
+        input_string ="Tact Coa"
+        input_string2 ="nick"
+        input_string3 ="saippuakivikauppias"
+        input_string4 = "iasppaukivikauppias"
+        self.assertTrue(palperm2(input_string))
+        self.assertFalse(palperm2(input_string2))
+        self.assertTrue(palperm2(input_string3))
+        self.assertTrue(palperm2(input_string4))
+
 if __name__ == '__main__':
     unittest.main()